The invention relates to a machine tool comprising at least one work spindle, as well as to a method for moving a workpiece or tool which is held on such a work spindle.
Today, highly precise spindle bearings predominantly equipped with anti-friction ball bearings are used. In view of achievable accuracies, rates of revolution, lubrication and useful life, such spindle bearings have been the subject of continuous development. Even though, in so doing, progress has certainly been made, current manufacturing possibilities do not allow any improvement regarding the radial and axial smoothness of running and the alignment of the supported shaft. It must be expected that some irregularities remain.
In order to deal with this problem, German publication DE 103 44 293 A1 has suggested a tool grinder comprising a machine adjustment device that initially defines the misalignment of a blank by means of an appropriate measuring device. The blank is then received by a workpiece receptacle on the working spindle. As the blank or the workpiece is being polished, this misalignment is taken into account and compensated for in that the grinding tools are guided to follow the workpiece in such a manner that the workpiece is being machined in a dimensionally stable and concentric manner, despite the misalignment.
In compensating for the wobbling motion of a workpiece that is cylindrical, for example, by means of a motion that is superimposed on the feed motion of the grinding tools, the superimposed motion is a function of the axial engagement position between the workpiece and the tool. Furthermore, referring to tools, which are not only in punctiform but linear, or even areal, engagement with the workpiece, the compensation can be difficult, or even impossible, as regards the compensation for a wobble of the workpiece by means of a movement of the tool, the workpiece being held on the rotating work spindle.
Considering this, the object to be achieved by the invention is an improved possibility for the compensation of misalignments of tools or workplaces on the work spindles.